DNA fragmentation (indicating programmed cell death; PCD) in untreated and chemical hybridization agent (CHA)-SQ-1-treated wheat plants during anther development.

<p>Anther sections in the DNase treatment (Positive control, A to E), untreated (F to J) and CHA-SQ-1-treated plants (K to O) were compared for nuclear DNA fragmentation using the TUNEL assay at the tetrad stage (A, F and K), early-uninucleate stage (B, G and L), later-uninucleate stage (C, H and M), binucleate stage (D, I and N) and trinucleate stage (E, J and O), respectively. Propidium iodide stained nuclei fluoresce red, while green fluorescence is TUNEL-positive nuclei staining. E, En, ML, T, Tds and Msp indicate the epidermis, the endothecium, the middle layer, the tapetum, the tetrads and the microspore, respectively. Scale bars are 50 μm.